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Soil Microorganisms and Nematodes for Bioremediation and Amelioration

dealing with the considerable accumulation of contaminants (both organic

and inorganic) in soil and water systems. As per an estimation made by

Blaylock et al. (1997), adoption of bioremediation technique for Pb polluted

soil could help reduce the cost by 50–65% compared to the conventional

methods. Literature is replete with case studies implying the use of microbes

as a successful clean-up strategy for both organic and inorganic pollutants.

Microbes alone or in association with plants have the ability to metabolize

a wide range of pollutants, categorically diverse in nature and properties,

either to obtain carbon and/or energy for growth and development or as

co-substrates. Despite numerous advantages of microbe-assisted bioreme­

diation, several limitations persist which often thwart the extrapolation of

lab carried experiments to field level showing unparalleled results. One

particular concern that persists is the long-term sustainability of the microbes

in bioremediation process. Considering the alarming rate of accumulation

of both organic and inorganic pollutants in the environment the microbial

bioremediation process should be fastened so as to match the available

commercial remediation processes.

Presence of more than one type of pollutants or a mixture of organic

pollutants and heavy metal(loid)s could obstruct the normal metabolic

functioning of the microbes. Therefore, the microbes need to be genetically

manipulated so as to introduce the required feature in the GEMs to increase

their endurance level to a wide array of pollutants without affecting its

remediation efficacy. In addition, genetic modification should be such that

the GEM should be able to modulate itself to the changing environmental

conditions. If at all the need of GEM arises then its introduction should

be backed up with thorough studies on its ecotoxicity, effect on existing

biodiversity and growth kinetics. Microbial techniques are the most logical,

long-term answer for remediation because the safe removal of large levels of

contaminants is a concern matched by greater worldwide awareness of the

environmental concerns caused by other approaches.

1.8 CONCLUSION AND FUTURE PROSPECTS

Natural and human activities are causing an increase in organic and inorganic

contaminants in the environment. In order to have a balanced and sustainable

ecosystem, these toxins must be removed and/or stabilized from the environ­

ment. Despite the fact that there have been several targeted studies in this

area, only a few strategies have been shown to be both safe and cost-effective.